Compatibility in PCI-E x16 and x1 card in Intel MB

lemoreno

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Aug 13, 2013
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10,510
Hi guys,

I have a problem and I haven't solved yet: I have 3 computers with a Intel DB75EN motherboard. In one of them I have to install 2 identical network cards (PCI-E x1). Motherboard has 2 PCI, 1 PCI-E x1 and 1 PCI-E x16, so I have installed one card in PCI-E x1 and the other one in PCI-E x16.

Here is where my problem starts: only card installed in PCI-E x1 is detected by BIOS. I changed position between cards, I tried in one of the other identical PC, but behavior is always the same: not working in PCI-E x16.

Finally, I have tried with both network cards in different motherboards with PCI-E x16 and it works!

I don't think my motherboard should be incompatible for this purpose. I have checked Intel page, and there is a page called "Tested Peripherals", where are mentioned some x4 cards, who should have been connected to x16 port

Link to MB description:
http://www.intel.com/content/www/us/en/motherboards/desktop-motherboards/desktop-board-db75en.html

Link to tested peripherals:
http://www.intel.com/support/motherboards/desktop/db75en/sb/CS-033661.htm

I hope you can give me some hints.

Regards!
Leo
 
Solution
It will depend on the chip set of the board in question.
And if it can switch the pci-e lanes of the card slot, for the card inserted.
Some boards can do this.

Others cannot, depending on the type of chip set and revision the board uses.

How the chip set treats each pci-e slot and it`s switching mode allocated to it.
It is down to the chip set of the board.

Some x16 pci-slots simply do not switch to a low enough lane, and are limited to x16, x8 or x4 modes putting a x1 card in the slot will render it unusable or not seen by the slot.


It will depend on the chip set of the board in question.
And if it can switch the pci-e lanes of the card slot, for the card inserted.
Some boards can do this.

Others cannot, depending on the type of chip set and revision the board uses.

How the chip set treats each pci-e slot and it`s switching mode allocated to it.
It is down to the chip set of the board.

Some x16 pci-slots simply do not switch to a low enough lane, and are limited to x16, x8 or x4 modes putting a x1 card in the slot will render it unusable or not seen by the slot.


 
Solution